In aviation, the autoland system fully automates the landing phase of an aircraft's flight, with the human crew supervising the process. Responding to external stimuli, the autoland system is primarily engaged in conditions of poor visibility and calm or steady winds.
A typical autoland system consists of an instrument landing system (ILS) radio, having an integrated glideslope receiver, localizer receiver, and perhaps GPS receiver as well, to receive the localizer and glideslope signals. The output of this radio will be a “deviation” from center which is provided to the flight control computer to direct the flight control system and aircraft control surfaces to maintain the aircraft centered on the localizer and glideslope. The flight control system will additionally control throttles to maintain the appropriate approach speed. After aircraft wheels-down, the autoland system may also include automatic braking to a full stop, in conjunction with the autobrake system, and sometimes auto deployment of spoilers and thrust reversers.
Auto-landing the aircraft is governed by stringent regulations to insure that the aircraft will land safely at the designated area on the runway (landing box) with a very high probability. Demonstrating compliance with those regulations is a very expensive process that includes simulations, flight testing, statistics, and analysis. Because the failure to perform the landing safely can cause catastrophic results, the associated systems have to go through the most rigorous Design Assurance Level (DAL), DAL A.